Full Frame vs APS-C cameras: what’s the real difference

With full-frame cameras becoming more ubiquitous and affordable in price, a new generation of digital photographers is waking up to the potential of shooting with high-resolution sensors.

But advances in technology in many crop-sensor cameras (such as Olympus’s Pixel Shift functionality) are allowing photographers who can’t afford – or don’t want to spend the money on – full frame to take equally large images up to 50MB in resolution.

So you might be asking yourself: do I really need a full-frame sensor? What’s the difference between full frame vs APS-C cameras?

Simply put, crop-sensor cameras are those that have image sensors that are smaller than a physical frame of 35mm film. If you can remember the 1990s, APS-C sensors (also called crop sensors) take their name from the old APS film format.

You’ll find an APS-C-size sensor in most entry-level and mid-range DSLRs as well as many mirrorless or compact system cameras (CSCs). They typically measure about 24x16mm, and you will find that cameras with these sensors produce images with a narrower angle of view. This is simply because they capture a smaller section of a scene than a full-frame camera can record.

Most interchangeable lens cameras launched in the last decade had APS-C sensors, so if you’ve been biding your time to upgrade, waiting for the technological developments to slow down, you’re probably now in a position where you’re considering whether to buy full frame or APS-C.

In this quick full frame vs APS-C comparison we’ll run through the key principles and differences that you need to know in order to make an informed decision to upgrade.

Full frame vs APS-C: Image quality

Provided you know what you’re doing technically, full frame cameras will generally give you a wider dynamic range than APS-C cameras with the same pixel count. However, at low sensitivity settings the smaller pixel size of APS-C sized sensors could actually enable you to capture more fine detail.

Full frame vs APS-C: Low light

Also related to image quality, a full frame camera will typically provide cleaner (noise-free) images in low light. With a full-frame camera you can more confidently push your ISO up to its higher settings, which for a night photographer might be all the motivation you need to upgrade to full frame.

Full frame vs APS-C: Viewfinder performance

If you like to compose images via your viewfinder rather than your Live View screen you’ll find that in a full frame camera your scenes will appear much brighter in the viewfinder. The reason for this is that a full-frame camera simply uses a larger mirror than its crop-sensor contemporaries.

Full frame vs APS-C: Body size

While you get more dynamic range, cleaner images at higher ISO settings and better resolution with full frame, the flip side is that you’re also getting a much larger camera body. For someone like me who shoots a lot of street photography and on-the-go, this is a deal-breaker.

For this reason I prefer a smaller camera body like my Fuji X-Pro1, which still offers a high-quality sensor. That said, you can now get a full-frame sensor in smaller system camera bodies, such as Sony’s A7 range. So increasingly, body size is ceasing to be a limitation.

Full frame vs APS-C: Depth of field

If you switch to a full-frame camera, no doubt one of the first things you will notice is a change in how your depth of field appears in your images. In other words, your out-of-focus areas will become more obvious.

For instance, if you mount a nifty fifty (50mm lens) on your new full-frame camera and shoot a landscape scene, you’d need a 35mm lens on an APS-C camera to capture the same angle of view. And the 35mm lens will give you much more depth of field because of its shorter focal length.

For the landscape photographer, the shallow depth of field you get from full frame might cause trouble for you. Portrait or macro photographers, however, might find this very advantageous.

Full frame vs APS-C: Lenses

Full-frame lenses can be costly (way more than your camera), but they never go obsolete. But even if you’re still saving to buy that expensive full-frame Nikon lens, you can still use your crop-factor lenses on a full frame Nikon camera.

Your camera will restrict the sensor area to an APS-C-size rectangle in the middle of the frame and you won’t get the benefit of your full-frame camera’s resolution, but the lenses will work just fine.

Canon EF-S (APS-C format) lenses, however, extend further into the body of the camera than do EF lenses. This can potentially damage your mirror assembly.

Full frame vs APS-C: Wider views

What’s more, you’ll find that full-frame lenses will give you a truer focal length when mounted on a full-frame camera. A wide-angle lens will deliver that wide angle without any clumsy math to determine the effective focal length.

Full frame vs APS-C: File size

It stands to reason that if you are shooting higher resolution images, your file sizes are going to be larger in turn – that’s true whether you shoot with a full-frame or cropped sensor camera. With this in mind, an upgrade to full frame may require investment in bigger capacity – and more expensive – memory cards.

Likewise, this will also have repercussions on how you back up these files, whether it’s an external drive or a cloud storage option.